This invention relates to a pre-energizer for a synchronizer.
Synchronizers for use in multi-ratio transmissions are well known. Such synchronizers may be of the single or double acting type and include pairs of friction and jaw members for respectively synchronizing and positive clutching a gear to a shaft, pre-energizer assemblies for engaging the friction members in response to initial engaging movement of a shift sleeve, a hub rotatably fixed to the shaft and having external spline teeth slidably receiving internal spline teeth of the shift sleeve which often defines one of the jaw member pairs, a baulking means having blocker teeth for arresting engaging movement of the shift sleeve until synchronization is reached and for transferring a shift force from the sleeve to increase the engaging force of the friction members.
It is also known that such synchronizers may be used to reduce shift time and shift effort required by a vehicle operator by the providing the synchronizes with self-energizing. EP-A-0663 541 discloses a synchronizer having all of the above.
An object of this invention is to provide a synchronizer with an improved pre-energizer.
The invention relates to a synchronizer for first and second drives disposed for relative rotation about a common axis, as disclosed in EP-A-0 663 541 which represents the precharacterizing part of claim. 1. The synchronizer comprises: A first element is affixed against rotation and axial movement relative to the first drive. A second element includes connecting means allowing sliding and non-rotational movement the second element relative to the first element, and includes first jaw means axially movable from a neutral position to an engaged position with second jaw means for positively connecting the drives in response to engaging movement of the second element by an axially directed first shift force; First friction means are axially movable into engagement with second friction means for synchronizing the first and second jaw means in response to the engaging movement of the second element. First and second blocker means are operative when engaged to prevent engagement of the first and second jaw means prior to the synchronizing. Pre-energizing means are for engaging the first and second friction means with an initial engaging force in response to initial engaging movement of the second element by the first shift force from the neutral position and for engaging the first and second blocker means in response to the initial engagement of the first and second friction means producing a synchronizing torque. First and second self-energizing means are operative when engaged to react the synchronizing torque for producing a first additive axial force in the direction of the first shift force and for increasing the engagement force of the first and second friction means. One of the first and second self-energizing means includes means for directing the first additive axial force to the first friction means via the first and second blocker means. The first self-energizing means is mounted on one of the elements and the second self-energizing means is mounted for non-radial movement and limited rotation relative to another of the elements.
The improvement is characterized by the pre-energizing means including first ramp means biased by resilient means toward engagement with second ramp means affixed to the second self-energizing means for transmitting the first shift force to the first friction means via the second self-energizing means and the first and second ramp means in response to the initial engaging movement of the second element.